ISIS announced (Aug. 6, 2017) that they have "secret weapons" that await coalition forces in Raqqa. Their usual approach is explosives, so one might assume it was just a variation on the explosives strategy. Their commander reportedly said, the Islamic State might unleash “other types of weapons which Allah has bestowed upon the Mujahidin and which we have not yet revealed.”
Historically, ISIS has bragged about having biological weapons, but these require a good bit of skill and discipline to develop. ISIS seems to have no problem recruiting suicide bombers, but clearly they haven't been recruiting suicide bio-bombers, whether by choice or just failure to recruit. By bio-bomber, I mean a suicidal attacker, infected with a lethal disease, with a purpose of infecting as many people as possible. Fortunately, the U.S. military has been preparing for this eventuality. If this is ISIS's "secret weapon" then it is fortunate that with the foresight of defensive training, planning and resources of the U.S. military, they have little chance of succeeding with it.
